***************************************************************************************************************

Size: px

Start display at page:

Download "***************************************************************************************************************"

Gary Watson
6 years ago
Views:

1 03450 ARCHITECTURAL PRECAST CONCRETE *************************************************************************************************************** SPECIFIER: CSI MasterFormat 2004 number *************************************************************************************************************** PART 1 GENERAL 1.1 SUMMARY A. Related Sections: Concrete Formwork Concrete Reinforcement Cast-in-Place Concrete Grout Joint Sealers 1.2 REFERENCES A. American Society for Testing and Materials (ASTM), latest edition: 1. A36/A36M Specification for Carbon Structural Steel. 2. A153 Specification for Zinc Coating (Hot-Dip) on Iron and Steel Hardware. 3. A307 Specification for Carbon Steel Bolts and Studs, 60,000 PSI Tensile Strength. 4. A416/A416M Specification for Steel Strand, Uncoated Seven-Wire for Prestressed Concrete. 5. C33 Specification for Concrete Aggregates. 6. C150 Specification for Portland Cement. 7. D2240 Standard Test Method for Rubber Property-Durometer Hardness. 1.3 QUALITY ASSURANCE A. Comply with provisions of the latest edition of the following codes, specifications and standards, except as otherwise indicated. 1. Prestressed Concrete Institute: Manual for Quality Control for Plants and Production of Precast Concrete Products (MNL-117). 2. ACI 318 Building Code Requirements for Reinforced Concrete including Commentary. 3. AWS Dl.4-79 Structural Welding Code - Reinforcing Steel. 4. AWS Dl.1-84: Structural Welding Code - Steel. 5. Applicable codes, specifications, and standards referenced in Sections 03100, 03200, and B. Fabricator Qualifications: Firms with 5 years successful experience in fabrication of precast concrete units similar to units required for this project. Fabricator must have sufficient production capacity to produce required units without causing delay in work. C. Fabrication Qualifications: Project No. SPECIFICATION GUIDELINES

2 1. Produce precast concrete units at fabrication plant engaged primarily in manufacturing of similar units, unless plant fabrication or delivery to site is impractical. 2. If units are produced at locations other than precast concrete fabricating plants, maintain procedures and conditions for quality control equivalent to plant production. D. Qualifications of Erector: Firms with a minimum of 5 years of successful experience in the erection of architectural precast concrete units, similar to units required for this project. E. Design modifications may be made only as necessary to meet field conditions and to ensure proper fitting of the work, and only as acceptable to A/E. 1. Maintain general design concept without increasing or decreasing sizes of members or altering profiles and alignment shown. 2. Provide complete design calculations and drawings prepared by a Florida registered professional engineer, if requested by A/E, if design modifications are anticipated. F. Fire-resistance Rated Precast Units: Where precast concrete units are shown or scheduled as requiring a fire-resistance classification, provide units tested and listed by UL or other OSHA approved Nationally Recognized Testing Laboratory (NRTL). Each unit shall bear appropriate label and marking indicating compliance with requirements of applicable building codes. 1.4 DESIGN A. Prestressed units shall be designed to comply with the latest requirements of the Florida Building Code (FBC) and ACI 318. B. Systems shall provide fire ratings as scheduled on the drawings. C. Design for self-weight of precast members plus other gravity and lateral loads shown on the drawings, or where loads are not shown, comply with applicable design loads of the FBC. 1.5 SUBMITTALS A. Product Data: 1. Submit manufacturer's specifications and instructions for manufactured materials and products. a. Include manufacturer's certifications and laboratory test reports as required. b. Submittals shall comply with applicable requirements of Sections 03100, and 03300, and shall include: 1) Curing and sealing compounds. 2) Proprietary reinforcing and pre-stressing connectors. 3) Expansion bearing assemblies. 4) Special handling instructions. B. Mix designs shall comply with Section Cast-in-Place Concrete, for classes of concrete, including provisions for control of total chloride ion content for prestressed members. Project No. SPECIFICATION GUIDELINES

3 C. Shop Drawings: 1. Shop drawings and manufacturer's complete design calculations shall be sealed by a current Florida registered professional engineer. 2. Submit shop drawings showing complete information for fabrication and installation of architectural precast concrete units. Indicate: a. Member dimensions. b. Location, size, and type of reinforcement, including special reinforcement and lifting devices necessary for handling and erection. c. Required strength at release. d. Detail inserts, connections, and joints, including accessories and construction at openings in precast units. 3. Provide layout, dimensions, and identification mark of each precast unit. Indicate welded connections by AWS standard symbols. Include erection procedure for precast units and sequence of erection. 4. Provide location, details, and instructions of anchorage devices to be embedded in other construction. Furnish templates if required for accurate placement. 5. Comply with applicable requirements of Sections 03100, 03200, for submittals of reinforcing and prestressing in precast units. D. Samples: 1. Submit 3 sets of precast samples approximately 12 inches x 12 inches x 2 inches to illustrate quality, color, and texture of surface finish. 2. Submit samples of cast-in gaskets, anchorages, and other attachments and accessories as requested by A/E. 3. Prepare full-size sample of each required architectural precast concrete unit for A/E s inspection at production plant or on site before start of installation work, and after A/E s review of finish samples. Acceptable full-size samples may be incorporated in job installation. 4. A/E's review of samples will be for color, texture, and general condition only. Compliance with other requirements is the responsibility of the Contractor. E. Production Records: During the course of production, maintain within the plant and be prepared to submit when and if requested by A/E the following data: 1. Casting Arrangement: Sequence, date, and time with each unit identified by shop drawing mark. 2. In-Plant Inspection Report: Signed by inspector and approved by a Florida registered professional engineer. 3. Concrete test reports. 4. Stressing records from pre-stressing including date and time of release. F. Certification: Upon completion of the erection of precast, manufacturer shall issue written certification that precast members have been installed according to approved shop drawings and design calculations, and according to the intent of the contract drawings. This certification shall bear the seal of the Florida registered professional engineer. Project No. SPECIFICATION GUIDELINES

4 1.6 DELIVERY, STORAGE, AND HANDLING A. Deliver architectural precast concrete units to project site in such quantities and at such times to assure continuity of installation. Store units at project site to insure against cracking, distortion, staining, or other physical damage, and with markings visible. Lift and support units at designated lift points. B. Deliver anchorage items to be embedded in other construction before start of such work. PART 2 PRODUCTS 2.1 FORMWORK A. Provide forms and, where required, form facing materials of metal, plastic, wood, or other acceptable materials non-reactive with concrete and will produce required finish surfaces. B. Accurately construct forms mortar tight and of sufficient strength to withstand pressures due to concrete placing operations, temperature changes, and when prestressed, pretensioning and detensioning operations. Maintain formwork to provide completed precast concrete units of shapes, sizes, and dimensions indicated, within specified fabrication tolerances. C. Unless forms for plant-manufactured prestressed concrete units are stripped before detensioning, design forms so stresses are not induced in precast units due to deformation of concrete under pre-stress or to movement during detensioning. D. Comply with ACI 347. E. Comply with applicable requirements of Section Concrete Formwork. 2.2 REINFORCING MATERIALS A. Comply with applicable requirements of Section Concrete Reinforcement. B. Use epoxy coated bars for precast on buildings where any part of the precast is within 1500 feet horizontally of a salt or brackish water body. 2.3 PRE-STRESSING TENDONS A. Uncoated, 7-wire stress-relieved strand complying with ASTM A416, Grade 270, lowrelaxation. 2.4 CONCRETE MATERIALS A. Comply with applicable requirements of Section Cast-in-Place Concrete, and as modified. B. Portland Cement: ASTM C150, Type I or Type III. 1. Use only one brand and type of cement throughout the project, unless otherwise acceptable to A/E. Project No. SPECIFICATION GUIDELINES

5 a. Use "buff" color Portland cement for facing concrete mix to match A/E's control sample, or use "white" Portland cement for facing concrete mix to match A/E's control sample. b. Standard "gray" Portland cement may be used for non-exposed back-up concrete. C. Coarse Aggregate for Facing Mixes: ASTM C33, hard, durable, carefully selected and graded, free of material causing staining or reacting with cement. D. Fine Aggregate for Facing Mixes: ASTM C33, manufactured sand of same material as coarse aggregate, unless otherwise acceptable to A/E. 2.5 CURING AND SEALING COMPOUNDS A. Comply with applicable requirements of Section 03300, Cast-in-Place Concrete. 2.6 CONNECTION MATERIALS A. Steel Shapes, Plates, and Bars: ASTM A36. B. Anchor Bolts: ASTM A307, Grade A or ASTM A36, low-carbon steel bolts, regular hexagon nuts, and carbon steel washers. C. Finish of Steel Units: Units exposed to non air-conditioned atmosphere in service shall be galvanized according to ASTM A153. Units exposed to air-conditioned atmosphere shall be painted with rust-inhibitive primer. *************************************************************************************************************** SPECIFIER: Specify bearing pads durometer hardness required for the project, *************************************************************************************************************** D. Bearing Pads: According to ASTM D2240, durometer hardness. E. Accessories: Provide clips, hangers, and other accessories required for installation of project units and for support of subsequent construction of finishes. 2.7 PROPORTIONING AND DESIGN OF MIXES A. Comply with applicable requirements at Section 03300, Cast-in-Place Concrete. Minimum 28 day strength shall be 5,000 psi. 2.8 CONCRETE MIXES A. Comply with applicable requirements of Section Cast-in-Place Concrete. B. Facing Mix: Standardizing concrete consisting of specified Portland cement, aggregates, admixtures, and water shall produce the following properties: 1. Compressive Strength: 5,000 psi minimum at 28 days. 2. Total Air Content: Not less than 4 percent nor more than 6 percent. Project No. SPECIFICATION GUIDELINES

6 C. Back-up Concrete: Standardizing concrete with compressive strength of 5,000 psi at 28 days or at contractor's option, lightweight concrete with 5,000 psi compressive strength at 28 days, and with air-dry density not less than 90 nor more than 115 pcf. 2.9 FABRICATION A. General: Fabricate precast concrete units complying with manufacturing and testing procedures, quality control recommendations, of PCI MNL-117, and as specified for types of units required. B. Fabricate units straight, smooth, and true to size and shape, with exposed edges and corners precise and square unless otherwise indicated. C. Warped, cracked, broken, spalled, stained, or otherwise defective precast units will not be acceptable. D. Built-In Items: Provide reglets, slots, holes, and other accessories in units to receive windows, dowels, reglets, waterstops, flashings, and other similar work as indicated. E. Built-in Anchorages: Accurately position built-in anchorage devices and secure to formwork. Locate anchorages where they do not affect position of main reinforcement of placing of concrete. Do not relocate bearing plates in units unless acceptable to A/E. F. Anchorages: Provide loose steel plates, clip angles, seat angles, anchors, dowels, clamps, hangers, and other miscellaneous steel shapes not provided by other trades, necessary for securing precast units to supporting and adjacent members. G. Coat surfaces of forms with bond-breaking compound before reinforcements are placed. Provide commercial formulation form-coating compounds that will not bond with, stain nor adversely affect concrete surfaces, and will not impair subsequent treatments of concrete surfaces requiring bond or adhesion. Apply according to manufacturers instructions. H. Clean reinforcement of loose rust and mill scale, dirt, and other materials capable of reducing or destroying bond with concrete. I. Accurately position, support, and secure reinforcement against displacement by formwork, construction, or concrete placement operation. Locate and support reinforcing by metal chairs, runners, bolsters, spacers, and hangers as required. J. Place reinforcement to obtain at least the minimum coverages for concrete protection. Arrange, space, and securely tie bars and bar supports to hold reinforcement in position during concrete placement operation. Set wire ties so ends are directed into concrete, not toward exposed concrete surfaces. K. Pretensioning of tendons for prestressed concrete may be accomplished either by single strand tensioning method or multiple-strand tensioning method. Comply with PCI MNL-117 requirements. L. Comply with plastic shrinkage requirements of Section 03300, Cast-in-Place Concrete during concrete placing operations. M. Place concrete in a continuous operation to prevent formation of seams or planes of weakness in precast units according to ACI 304. Thoroughly consolidate concrete by Project No. SPECIFICATION GUIDELINES

7 internal and external vibration without dislocation or damage to reinforcement and built-in items. N. Identification: Provide permanent markings to identify pick-up points and orientation in structure, according to with markings indicated on final shop drawings. Imprint date of casting on each precast unit on a surface not showing in finished structure. O. Curing by low-pressure steam, by steam vapor, by radiant heat and moisture, or other similar process may be employed to accelerate concrete hardening and to reduce curing time. P. Delay detensioning of prestressed units until concrete has attained a design strength consistent with the design, as established by test cylinders. Q. Surface Finish: Fabricate precast units and provide exposed surface finishes, to match A/E's control sample as follows: 1. Abrasive Blast Finish: Using abrasive grit, equipment, application techniques, and cleaning to expose aggregate and surrounding matrix surfaces. 2. Exposed Aggregate Finish: Using chemical retarding agents applied to concrete forms, with washing and brushing procedures after form removal. 3. Bushhammer Finish: Using power and hand tools and cleaning procedures. 4. Smooth Surface Finish: Uniform color and texture, and free of pockets, sand streaks, and honeycomb. 5. Textured Surface Finish: Imparted by form liners or inserts to provide surfaces free of pockets, and streaks and honeycomb, with uniform color and texture. 6. As-cast or Float Finish: For unexposed surfaces. PART 3 EXECUTION 3.1 EXAMINATION A. Erector shall examine supporting structure and conditions the precast concrete work is to be erected. B. Notify contractor in writing of conditions detrimental to proper and timely completion of work. C. Do not proceed with installation until unsatisfactory conditions have been corrected in a manner acceptable to erector. 3.2 INSTALLATION A. General: 1. Deliver anchorage items to be embedded in other construction before start of such work. 2. Provide setting diagrams, templates, instructions, and directions as required for installation. B. Do not install precast units until concrete has attained its design compressive strength. Project No. SPECIFICATION GUIDELINES

8 C. Install precast concrete members plumb, level, and in alignment within PCI MNL-17 specified limits of erection tolerances. 1. Provide temporary supports members as being permanently connected. 2. Maintain horizontal and vertical joint alignment and uniform joint width as erection progresses. D. Accessories: Install clips, hangers, and other accessories required for erection of precast units to supporting members and back-up materials. E. Anchor units in final position by bolting, welding, grouting, or as otherwise indicated. Remove temporary shims, wedges, and spacers as soon as possible after anchoring is completed. 1. At bolted connections, use lock washers or other acceptable means to prevent loosening of nuts. 2. At welded connections apply rust inhibitive coating on damaged areas, same as shop applied material. Use galvanized repair coating on galvanized surfaces. F. Bearing Pads: 1. Install flexible bearing pads where indicated, as precast units are being erected. 2. Set pads on level, uniform bearing surfaces and maintain in correct position until precast units are placed. G. Welding: Perform welding according to AWS Dl.1-86 and AWS Dl.4-79, including qualification of welders and submittal of procedure specification for welds used. H. Protect units from damage by field welding or cutting operations and provide noncombustible shield as required. I. Grouting Connections and Joints: After precast concrete units have been placed and secured, grout open spaces at connections and joints with cement grout according to Sections and J. Cleaning: 1. Clean exposed facings to remove dirt and stains on units after erection and completion of joint treatments. 2. Wash and rinse according to precast manufacturer s recommendations. Protect other work from damage due to cleaning operations. 3. Do not use cleaning materials or processes capable of changing the character of exposed concrete finishes. 3.3 PERFORMANCE REQUIREMENTS A. Conduct inspections, perform testing, and make repairs or replace unsatisfactory precast units as required. B. In place precast units may be rejected for any one of the following: 1. Exceeding the specified installation tolerances. 2. Damaged during construction operations. Project No. SPECIFICATION GUIDELINES

9 3. Exposed-to-view surfaces with surface finish deficiencies. 4. Other defects as listed in PCI MNL PLANT QUALITY CONTROL EVALUATIONS A. The Board may employ a separate testing laboratory to evaluate precast manufacturer's quality control and testing methods. B. The precast manufacturer shall allow the Board's testing laboratory access to materials storage areas, concrete production equipment, and concrete placement and curing facilities. Cooperate with the Board's testing laboratory and provide samples of materials and concrete mixes as may be requested for additional testing and evaluation. C. Dimensional Tolerances: 1. Units having dimensions smaller or greater than required, and outside specified tolerance limits, will be subject to additional testing as specified. 2. Precast units having dimensions greater than required will be rejected if appearance of function or the structure is adversely affected, or if larger dimensions interfere with other construction. Repair, or remove and replace rejected units as required to meet construction conditions. D. Defective Work: 1. Precast concrete units not complying with specified requirements, including strength, tolerances, and finishes shall be replaced with precast concrete units meeting requirements of this section. 2. The contractor shall also be responsible for the cost of corrections to any other work affected by or resulting from corrections to precast concrete work. END OF SECTION Project No. SPECIFICATION GUIDELINES

SECTION ARCHITECTURAL PRECAST CONCRETE. A. American Society for Testing and Materials (ASTM):

SECTION ARCHITECTURAL PRECAST CONCRETE. A. American Society for Testing and Materials (ASTM): SECTION 03450 ARCHITECTURAL PRECAST CONCRETE PART 1 GENERAL 1.01 SUMMARY A. Related Sections: 1. 03100 - Concrete Formwork 2. 03200 - Concrete Reinforcement 3. 03300 - Cast-in-Place Concrete 4. 03600 -